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JOB SURVEYS
Knowledge of rainfall and climate, end use of the land,
and job specifications can be obtained from records,
surveys, engineering studies, and written specifications.
You should personally review the land to be cleared to
gain other necessary and valuable information.
The survey should include a study of general topog-
raphy and soil conditions. Note such problem factors
as hills, rocks, or swamps which would significantly affect
production or which would require special treatment.
Cruise the area to be cleared and determine the acreage
of each vegetative type (i.e. upland woods, low timber-
lands, swamps). Make at least three tree counts at random
for each vegetation type. To conduct these counts, ran-
domly locate two points 100 meters (328 feet) apart. Count
and measure vegetative growth along a straight line between
these points for a width of about 5 meters (16 feet) on both
sides. This gives the population of 1/10 hectare (1/4 acre).
1. Density of vegetation less than 30 cm (12 in) diameter
Dense — 1480 trees/hectare or more
(600 trees/acre)
Medium — 990-1480 trees/hectare
(400-600 trees/acre)
Light — less than 990 trees/hectare
(400 trees/acre)
2. Presence of hardwoods expressed in percent
3. Presence of heavy vines
4. Average number of trees per hectare (2.47 acres) in
each of the following ground level diameter size ranges:
Less than 30 cm (1 ft)
31 cm-60 cm (1-2 ft)
61 cm-90 cm (2-3 ft)
91 cm-120 cm (3-4 ft)
121 cm-180 cm (4-6 ft)
5. Sum of diameter of all trees per hectare (2.47 acres)
above 180 cm (6 ft) in diameter at ground level.
CLEARING METHODS AND EQUIPMENT
Methods for Initial Felling
— There are several
methods indicating the degree of clearing for initial
felling and several types of equipment for use with
each method. Equipment use in different size vege-
tation and different size areas is summarized in the
table on the next page. This information should serve
only as a rough guideline in selecting equipment. The
economical land area for each type of equipment will
vary with the capital cost of equipment and moving
cost. It is also affected by whether there are alternate
uses for equipment such as using tractors for other
construction work or tillage.
Land Clearing Machines
— Job size, severity of job
such as tree size, and time limit to complete will influ-
ence machine selection. Some machines, such as pur-
pose built forestry equipment and track-type tractors
are more suited for this type of work than others, but
imagination and resourcefulness can allow the use of
other types of machines in specific applications. For
example, loaders are used more today in raking and pil-
ing operations than ever before.
Operator Protection and Machine Guarding
— Daily
production has been estimated to increase 20% when
cab guards are used. Cabs designed specifically for for-
estry and clearing applications are available on purpose
built Cat
®
forestry equipment. Auxiliary equipment manu-
facturers such as Rome™ offer after market guard pack-
ages for non-purpose built units.
Locally designed and manufactured guarding for non-
purpose built equipment is required. The radiator, engine,
and underside of the tractor must be well protected. Perfo-
rated hoods, screens, crankcase guards and hydraulic
cylinder guards are generally recommended.
Generally speaking lower cost clearing can be done
with purpose built forestry equipment and larger trac-
tors if the amount of clearing involved is sufficient to
merit the initial investment of purpose built or if the
amount of clearing involved is sufficient to merit the
initial investment in the bigger machine. In applications
where track-type tractors are used, power shift transmis-
sions should be standard due to the frequent direction
changes. The direct drive transmission tractor is rec-
ommended when the tractor is used principally in con-
stant drawbar work such as chaining or pulling a disc
harrow. In most applications, a winch should also be
considered on one of every three tractors in a fleet.
27-2 Edition 47
Job Surveys
Methods and Equipment
Land Clearing